It is common in many different manufacturing processes to require that pieces of an assembly be located in a precise orientation, either temporarily or permanently. One widely-used method to accomplish this positioning is a tab and a slot type joint. In this type of assembly joint, the slot is formed in one of the pieces and the tab is formed in the other of the pieces to be mated. Normally, the tab and the slot combination is designed to achieve a noncontacting fit ensuring ease of assembly. Each of the slot and the tab is sized so that the tab will slide easily into the slot. In such applications, a rectangular cross-sectional configuration is used for each of the tab and the slot. The tab and slot method is normally, but not necessarily, used to connect pieces in a perpendicular orientation.
There are two main methods used to connect the pieces using the tab and slot joint. A first widely used method is to simply insert the tab into the slot. This method is disclosed in U.S. Pat. No. 5,190,207 issued on Mar. 2, 1993 to Peck et al. This method acts to provide a guide for the relative positioning of the pieces. After the initial positioning is established, a fastening method, usually welding, is used to fixedly attach the pieces. For example, the area approximate the tab and the slot are welded, forming a fixed joint. This method has the disadvantage of the pieces being loosely connected prior to being welded. Thus, the positioning of the tab relative to the slot, and vice versa, is imprecise and provides a great variation in the desired preestablished position. The joint resulting from this fastening method gives a loose fit between the tab and the slot prior to welding.
A second commonly used method comprises an elongated tab having a narrowed neck portion located near the intersection of the tab and the piece to be connected which contains the slot. After the tab is inserted into the slot, the elongated portion is rotated about the narrowed neck portion. Thus, the twisted tab cannot pull back through the slot to disassemble the pieces. The pieces are then permanently joined as in the previous method such as by welding. Once the two pieces are more permanently joined, the tab is commonly broken off by severing or tearing at the narrowed neck portion. This second method may be more precise than the previous one, however, the labor needed to twist the tabs and then sever or tear the remainder of the tab is timeconsuming. The scrap produced when forming the elongated tabs and the severed or torn tab is wasteful, as well.
The present invention is directed to overcoming one or more of the problems as set forth above.